Stent with anti-migration features

ABSTRACT

An implantable medical device for implantation within a passageway of a patient comprises a stent including a plurality of wires, at least one of the plurality of wires having a cross-section having a first tapered point, and a covering layer having an inner diameter and an outer diameter. In some embodiments, the plurality of wires may be disposed at least partially around the covering layer. Additionally in some embodiments, the first tapered point may extend outward further than the outer diameter of the covering layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/055,510, filed Feb. 26, 2016, which claims priority to U.S.Provisional Application No. 62/127,486, filed Mar. 3, 2015, the entiredisclosures of which are herein incorporated by reference.

TECHNICAL FIELD

The disclosure is directed to an endoprosthesis, such as a stent,including anti-migration features. More particularly, the disclosure isdirected to an endoprosthesis, such as a stent, including wires with oneor more projections.

BACKGROUND

An endoprosthesis may be configured to be positioned in a body lumen fora variety of medical applications. For example, an endoprosthesis may beused to treat a stenosis in a blood vessel, used to maintain a fluidopening or pathway in the vascular, urinary, biliary, tracheobronchial,esophageal or renal tracts, or to position a device such as anartificial valve or filter within a body lumen, in some instances. Bareor partially covered endoprostheses allow tissue ingrowth through thestructure of the endoprosthesis to prevent migration of theendoprosthesis. However, if it is desired to remove the endoprosthesisat some later time, the ingrown tissue must be cut away, causingsignificant trauma to the body lumen. Fully covered endoprostheses, onthe other hand, prevent tissue ingrowth to facilitate removal. However,fully covered endoprostheses are prone to migrate through the bodylumen. Accordingly, it is desirable to provide endoprostheses thatexhibit anti-migration features, while reducing the trauma to the bodylumen of the patient if removal of the endoprosthesis is desired.

BRIEF SUMMARY

The disclosure is directed to several alternative designs, materials andmethods of manufacturing medical device structures and assemblies, anduses thereof.

In one embodiment, an implantable medical device for implantation withina passageway of a patient comprises a framework including a plurality ofwires. At least one of the plurality of wires may have a cross-sectionhaving a first tapered point. The implantable medical device may furthercomprise a covering layer having an inner diameter and an outerdiameter. Additionally, the covering layer covers at least a portion ofthe framework, and the first tapered point may extend outward furtherthan the outer diameter of the covering layer.

Additionally, or alternatively, in the above embodiment, the at leastone of the plurality of wires may have a cross-section having a secondtapered point.

Additionally, or alternatively, in any of the above embodiments, thesecond tapered point may extend inward further than the outer diameterof the covering layer

Additionally, or alternatively, in any of the above embodiments, thesecond tapered point may extend inward further than the inner diameterof the covering layer.

Additionally, or alternatively, in any of the above embodiments, thecross-section of the at least one of the plurality of wires may furthercomprise a third tapered point.

Additionally, or alternatively, in any of the above embodiments, thecross-section of the at least one of the plurality of wires may betriangular.

Additionally, or alternatively, in any of the above embodiments, the atleast one of the at least one of the plurality of wires may have across-section having a rectangular projection.

Additionally, or alternatively, in any of the above embodiments, thefirst tapered point may extend outward in a direction opposite thesecond tapered point.

Additionally, or alternatively, in any of the above embodiments, thesecond tapered point may be embedded into the covering layer.

Additionally, or alternatively, in any of the above embodiments, thecovering layer may further have a central longitudinal axis, and whereinthe first tapered point extends radially outward relative to the centrallongitudinal axis.

Additionally, or alternatively, in any of the above embodiments, atleast one of the plurality of wires may be made from a Nickel Titaniumalloy.

Additionally, or alternatively, in any of the above embodiments, theframework may be a self-expanding framework.

Additionally, or alternatively, in any of the above embodiments, thecovering layer may be made from a biocompatible polymer.

Additionally, or alternatively, in any of the above embodiments, thecovering layer may be flexible.

Additionally, or alternatively, in any of the above embodiments, whereinthe first tapered point may extend outward from the outer diameter ofthe covering layer between 0.1 mm and 1.0 mm.

This disclosure also relates to a method of forming an implantablemedical device comprising positioning a covering layer over a mandreland weaving a plurality of wires over the covering layer to form astent, the covering layer having a central longitudinal axis and aninner diameter and an outer diameter, and at least one of the pluralityof wires having a cross-section including a first tapered point. In someembodiments, the plurality of wires are woven over the covering layersuch that the first tapered point of the at least one of the pluralityof wires extends outward away from the central longitudinal axis furtherthan the outer diameter of the covering layer. In some embodiments, themethod may further comprise removing the stent and the covering layerfrom the mandrel.

Additionally, or alternatively, in the above embodiment, wherein the atleast one of the plurality of wires has a cross-section having a secondtapered point, and further comprising embedding the second tapered pointin the covering layer.

Additionally, or alternatively, in any of the above embodiments, themethod may further comprise positioning the covering layer over amandrel.

Additionally, or alternatively, in any of the above embodiments, themethod may further comprise embedding the first tapered point in thecovering layer.

Additionally, or alternatively, in any of the above embodiments, the atleast one of the plurality of wires may have a cross-section having asecond tapered point.

Additionally, or alternatively, in any of the above embodiments, themethod may further comprise embedding the second tapered point in thecovering layer.

Additionally, or alternatively, in any of the above embodiments, thesecond tapered point may extend inward further than the outer diameterof the covering layer.

Additionally, or alternatively, in any of the above embodiments, thesecond tapered point may extend inward further than the inner diameterof the covering layer.

Additionally, or alternatively, in any of the above embodiments, thefirst tapered point may extend outward in a direction opposite thesecond tapered point.

Additionally, or alternatively, in any of the above embodiments, thecovering layer may be flexible.

Additionally, or alternatively, in any of the above embodiments, thecovering layer may be a polymeric tubular member.

In another embodiment, a method of forming an implantable medical devicemay comprise weaving a plurality of wires to form a woven frameworkcomprising a plurality of open cells, the framework having a centralhollow region, at least one of the plurality of wires having across-section including a first tapered point. In some embodiments, themethod may further comprise inserting a compliant filler into thecentral hollow region of the woven framework and covering the wovenframework and the compliant filler with a cover material. Finally, themethod may further comprise removing the compliant filler.

Additionally, or alternatively, in the above embodiment, the covermaterial may not adhere to the compliant filler.

Additionally, or alternatively, in any of the above embodiments, whenthe compliant filler is inserted into the central hollow region of thewoven framework, an outer portion of the compliant filler may extend atleast partially into one or more of the plurality of open cells.

Additionally, or alternatively, in any of the above embodiments,covering the woven framework and the compliant filler with a covermaterial may comprise one or more of: dipping the woven framework andthe compliant filler in the cover material; spraying the cover materialonto the woven framework and the compliant filler; and heat shrinkingthe cover material onto the woven framework and the compliant filler.

The above summary is not intended to describe each embodiment or everyimplementation of the present disclosure. Advantages and attainments,together with a more complete understanding of the disclosure, willbecome apparent and appreciated by referring to the followingdescription and claims taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects of the disclosure may be further understood in considerationof the following detailed description of various embodiments inconnection with the accompanying drawings, in which:

FIG. 1 is a schematic illustration of a patient showing a stent disposedwithin the patient's esophagus, in accordance with embodiments of thepresent disclosure;

FIG. 2 is a perspective view of an exemplary endoprosthesis, inaccordance with embodiments of the present disclosure;

FIG. 3 is a view of a longitudinal cross-sectional configuration of thewires of the endoprosthesis of FIG. 2 as viewed along line 3-3;

FIG. 4 is a view of a transverse cross-sectional configuration of theendoprosthesis of FIG. 2 as viewed along line 4-4;

FIG. 5 is an alternative longitudinal cross-sectional configuration ofthe wires of the endoprosthesis of FIG. 2 taken along line 3-3;

FIG. 6 is an alternative transverse cross-sectional configuration of thewires of the endoprosthesis of FIG. 2 taken along line 4-4;

FIG. 7 is another alternative longitudinal cross-sectional configurationof the wires of the endoprosthesis of FIG. 2 taken along line 3-3;

FIG. 8 is another alternative transverse cross-sectional configurationof the wires of the endoprosthesis of FIG. 2 taken along line 4-4;

FIGS. 9A-9E are example cross-sections of wires of an endoprosthesis, inaccordance with embodiments of the present disclosure;

FIGS. 10-14 are example cross-sections of an endoprosthesis including acovering layer, in accordance with embodiments of the presentdisclosure;

FIGS. 15-19 are example cross-sections of an endoprosthesis including acovering layer, in accordance with embodiments of the presentdisclosure;

FIGS. 20-24 are example cross-sections of an endoprosthesis including acovering layer, in accordance with embodiments of the presentdisclosure;

FIG. 25 is an example cross-section of an endoprosthesis including acovering layer during forming of the endoprosthesis, in accordance withembodiments of the present disclosure;

FIG. 26 is another example cross-section of an endoprosthesis includinga covering layer during forming of the endoprosthesis, in accordancewith embodiments of the present disclosure;

FIG. 27 is an example cross-section of an endoprosthesis including acovering layer after forming of the endoprosthesis, in accordance withembodiments of the present disclosure;

FIG. 28 is an example cross-section of an endoprosthesis including acovering layer during forming of the endoprosthesis, in accordance withembodiments of the present disclosure;

FIGS. 29A and 29B are more example cross-sections of an endoprosthesisincluding a covering layer during forming of the endoprosthesis, inaccordance with embodiments of the present disclosure; and

FIG. 30 is a flow diagram of a method of forming an endoprosthesis, inaccordance with the present disclosure.

While the aspects of the disclosure are amenable to variousmodifications and alternative forms, specifics thereof have been shownby way of example in the drawings and will be described in detail. Itshould be understood, however, that the intention is not to limitaspects of the disclosure to the particular embodiments described. Onthe contrary, the intention is to cover all modifications, equivalents,and alternatives falling within the spirit and scope of the disclosure.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

Definitions of certain terms are provided below and shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about”, whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the term “about” may be indicative asincluding numbers that are rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4,and 5).

Although some suitable dimensions, ranges and/or values pertaining tovarious components, features and/or specifications are disclosed, one ofskill in the art, incited by the present disclosure, would understanddesired dimensions, ranges and/or values may deviate from thoseexpressly disclosed.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include or otherwise refer to singular aswell as plural referents, unless the content clearly dictates otherwise.As used in this specification and the appended claims, the term “or” isgenerally employed to include “and/or,” unless the content clearlydictates otherwise.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The detailed description and the drawings, which are notnecessarily to scale, depict illustrative embodiments and are notintended to limit the scope of the disclosure. The illustrativeembodiments depicted are intended only as exemplary. Selected featuresof any illustrative embodiment may be incorporated into an additionalembodiment unless clearly stated to the contrary.

FIG. 1 provides a schematic illustration of the torso of a patient 10.The patient 10 includes an esophagus 14 leading to stomach 16. Anendoprosthesis 18 may be seen in phantom, disposed within the esophagus14. It will be appreciated that this placement is merely forillustrative purposes, as endoprosthesis 18 may be deployed elsewhere inesophagus 14. It will also be appreciated that while endoprosthesis 18is described herein as an esophageal stent, endoprosthesis 18 may bedeployed in a variety of other bodily lumens, including but not limitedto the vascular, urinary, biliary, tracheobronchial, esophageal or renaltracts. Although illustrated as a stent, endoprosthesis 18 may be any ofa number of devices that may be introduced endoscopically,subcutaneously, percutaneously or surgically to be positioned within anorgan, tissue, or lumen, such as a heart, artery, vein, urethra,esophagus, trachea, bronchus, bile duct, or the like.

A difficulty in placing endoprosthesis 18 in esophagus 14 is thatperistalsis of esophagus 14 may cause endoprosthesis 18 to migrate awayfrom the initial implant site. Accordingly, in some embodiments,endoprosthesis 18 may be configured to help hold the endoprosthesis 18in place within the esophagus 14. Endoprosthesis 18 may be held in placefrictionally, for example between the walls of esophagus 14 and one ormore features of endoprosthesis 18.

FIG. 2 illustrates an exemplary endoprosthesis 20. Endoprosthesis 20 mayinclude a first end 24, a second end 26, and a woven wire framework 22,such as a stent, disposed about a longitudinal axis of endoprosthesis 20that defines a lumen 28 extending therethrough. The term ‘woven wireframework 22’ may be referred to as ‘wire framework 22’ hereafter. Thewire framework 22 may include one or more wires 21 which cross orotherwise interconnect to form a mesh-like structure of the wireframework 22, including a plurality of open cells 30. Wire framework 22may be configured to transition from a compressed state to an expandedstate.

Endoprosthesis 20 may be configured to be implanted in the vasculatureof a patient, such as an aortic ostium, tortuous vessels, etc. In otherembodiments, endoprosthesis 20 may be configured to be implanted in theurinary, biliary, tracheobronchial, esophageal or renal tracts, forexample. Endoprosthesis 20, or a portion thereof, may be made from abiostable material, a bioabsorbable material, or a combination thereof.Examples of the biostable metal materials may include, but are notlimited to, stainless steel, tantalum, tungsten, niobium, platinum,nickel-chromium alloys, cobalt-chromium alloys such as Elgiloy® andPhynox®, nitinol (e.g., 55% nickel, 45% titanium), and other alloysbased on titanium, including nickel titanium alloys, or other suitablemetals, or combinations or alloys thereof. Some suitable biostablepolymeric materials include, but are not necessarily limited to,polyamide, polyether block amide, polyethylene, polyethyleneterephthalate, polypropylene, polyvinylchloride, polyurethane,polytetrafluoroethylene, polysulfone, and copolymers, blends, mixturesor combinations thereof. Examples of suitable bioabsorbable materialsmay include polymers, such as poly-L-lactide (PLLA), polyglycolide(PGA), polylactide (PLA), poly-D-lactide (PDLA), polycaprolactone,polydioxanone, polygluconate, polylactic acid-polyethylene oxidecopolymers, modified cellulose, collagen, poly(hydroxybutyrate),polyanhydride, polyphosphoester, poly(amino acids), and combinationsthereof.

FIGS. 3 and 4 depict example cross-sectional configurations of the wiresof an example endoprosthesis 20 taken along lines 3-3 and 4-4 of FIG. 2,respectively. FIG. 3 depicts endoprosthesis 20 having a centrallongitudinal axis 47 running through the center of endoprosthesis 20.Additionally, in the embodiments of FIGS. 3 and 4, the one or more wires21 of endoprosthesis 20 may have a cross-section including a firsttapered point 43. In at least some embodiments, first tapered point 43may extend generally away from central longitudinal axis 47. Although inFIGS. 3 and 4, first tapered point 43 is depicted generally extendingperpendicularly to central longitudinal axis 47, in other embodiments,first tapered point 43 may be disposed rotated with respect to centrallongitudinal axis 47 such that there may be an angle anywhere betweengreater than 0 degrees and less than 90 degrees between centrallongitudinal axis 47 and a line extending from first tapered point 43 inthe direction of the taper. In other embodiments, the range of the anglemay be between 15 degrees and 75 degrees or between 30 degrees and 60degrees, for example, and in some particular examples, the angle may beabout 35 degrees, about 45 degrees, or about 55 degrees, for instance.

Additionally, in some embodiments, the cross-section of the one or morewires 21 may have one or more additional tapered points, such as asecond tapered point 49. Second tapered point 49 may generally extendoutward from the center of the cross-section of the one or more wires 21in a direction different than first tapered point 43. In some furtherembodiments, the cross-section of the one or more wires 21 may includeone or more additional tapered points, such as a third tapered point 51,which may generally extend outward from the center of the cross-sectionof the one or more wires 21 in a direction different than either offirst tapered point 43 and second tapered point 49. In at least some ofthese embodiments, the cross-section of the one or more wires 21including tapered points 43, 49, and 51 may form a triangle shape.However, in other embodiments, the cross-section of the one or morewires 21 may form other shapes. Additionally, as depicted in FIGS. 3 and4, tapered points 49 and 51 extend generally parallel to centrallongitudinal axis 47, causing face 45 to be generally parallel tocentral longitudinal axis 47, in other examples, the one or more wires21 may be rotated in any manner with respect to central longitudinalaxis 47 that face 45 may extend at any angle with respect to centrallongitudinal axis 47.

FIGS. 5 and 6 depict additional alternative cross-sectionalconfigurations of the wires of an example endoprosthesis 20 taken alonglines 3-3 and 4-4 of FIG. 2, respectively. FIG. 5 depicts endoprosthesis20 having a central longitudinal axis 47 running through the center ofendoprosthesis 20. Additionally, in the embodiments of FIGS. 5 and 6,the one or more wires 21 of endoprosthesis 20 may have a cross-sectionincluding at least a first tapered point 61 and a second tapered point65. In at least some embodiments, first tapered point 61 may extendgenerally away from the center of the cross-section of the one or morewires 21 in a first direction and second tapered point 65 may extendgenerally away from the center of the cross-section of the one or morewires 21 in a second direction that is generally opposite the firstdirection, although in other embodiments this is not required.Additionally, first tapered point 61 may extend generally away fromcentral longitudinal axis 47 while second tapered point 65 may extendgenerally toward central longitudinal axis 47. As depicted in FIGS. 5and 6, first and second tapered points 61, 65 extend generallyperpendicular to central longitudinal axis 47, however, in otherexamples, the one or more wires 21 may be rotated such that first andsecond tapered points 61, 65 extend at any angle with respect to centrallongitudinal axis 47.

Additionally, in some embodiments, the cross-section of the one or morewires 21 may further include one or more additional tapered points, suchas third and fourth tapered points 63, 67. Third and fourth taperedpoints 63, 67 may generally extend outward from the center of thecross-section of the one or more wires 21 in third and fourthdirections, which may be different than the first and second directions.The third and fourth directions may generally be opposite, but this isnot required in all embodiments. In at least some of these embodiments,the cross-section of the one or more wires 21 including tapered points61, 63, 65, and 67 may form a diamond shape. However, in otherembodiments, the cross-section of the one or more wires 21 may formother shapes. Additionally, as depicted in FIGS. 5 and 6, third andfourth tapered points 63 and 67 extend generally parallel to centrallongitudinal axis 47, in other examples, the one or more wires 21 may berotated in any manner with respect to central longitudinal axis 47 thatthird and fourth tapered points 63, 67 may extend at any angle withrespect to central longitudinal axis 47.

FIGS. 7 and 8 depict additional alternative cross-sectionalconfigurations of the wires of an example endoprosthesis 20 taken alonglines 3-3 and 4-4 of FIG. 2, respectively. FIG. 7 depicts endoprosthesis20 having a central longitudinal axis 47 running through the center ofendoprosthesis 20. Additionally, in the embodiments of FIGS. 7 and 8,the one or more wires 21 of endoprosthesis 20 may have a cross-sectionincluding at least a first tapered point 71, a second tapered point 75,and a first projection 73. In at least some embodiments, first taperedpoint 71 may extend generally away from the center of the cross-sectionof the one or more wires 21 in a first direction and second taperedpoint 75 may extend generally away from the center of the cross-sectionof the one or more wires 21 in a second direction that is generallyopposite the first direction. Additionally, first tapered point 71 mayextend generally away from central longitudinal axis 47 while secondtapered point 75 may extend generally toward central longitudinal axis47. As depicted in FIGS. 7 and 8, first and second tapered points 71, 75extend generally perpendicular to central longitudinal axis 47, however,in other examples, the one or more wires 21 may be rotated such thatfirst and second tapered points 71, 75 extend at any angle with respectto central longitudinal axis 47. Further, first projection 73 maygenerally extend outward from the center of the cross-section of wire 21in a third direction that is different than both the first and seconddirections. In some embodiments, first projection 73 may be a generallysquared shaped, however, in other embodiments, first projection 73 maybe round, or trapezoidal, or any other suitable shape.

Additionally, in some embodiments, the cross-section of the one or morewires 21 may further include one or more additional projections, such asa second projection 77. Second projection 77 may generally extendoutward from the center of the cross-section the one or more wires 21 ina fourth direction that is different than any of the first, second, andthird directions. Additionally, in some embodiments, the fourthdirection may general be opposite the third direction, although this isnot required. Although the third and fourth directions depicted in FIGS.7 and 8 are generally parallel to central longitudinal axis 47, in otherembodiments the one or more wires 21 may be disposed rotated withrespect to central longitudinal axis 47 such that the third and fourthdirections are disposed at any angle with respect to centrallongitudinal axis 47. Additionally, as with first projection 73, secondprojection 77 may be general squared shaped. However, in otherembodiments, second projection 77 may be round, or trapezoidal, or anyother suitable shape, and may be differently shaped than firstprojection 73.

FIGS. 9A-9E depict additional example cross-sectional shapes that theone or more wires 21 may have. FIG. 9A depicts a parallelogram 91.Parallelogram 91 may have four sides 92 a-92 d, where sides 92 a and 92b may be of the same length and sides 92 c and 92 d may be of the samelength, with the length of sides 92 a and 92 b being different than thelength of sides 92 c and 92 d. Side 92 a may intersect with sides 92 cand 92 d to form angles Y and X, respectively. Similarly, side 92 b mayintersect with sides 92 c and 92 d to form angles X and Y, respectively.FIG. 9B depicts square 93 having four equal length sides 94. Eachintersection of two sides 94 may form right angles Z. FIG. 9C depictsrhombus 95. Rhombus 95 includes four equal length sides 96. In contrastto square 94, sides 96 may intersect with each other as depicted to formtwo different angles, angles A and B.

FIG. 9D depicts trapezoid 97. Trapezoid 97 has four sides 98 a-98 d, inwhich at least one side has a length different than the other sides. Asdepicted, side 98 a may intersect with side 98 b to form obtuse angle D,and side 98 b may intersect with side 98 c to form acute angle E. Side98 c may intersect with side 98 d to form acute angle F, and side 98 dmay intersect with side 98 a to form obtuse angle C. Additionally, sides98 a and 98 c may be disposed parallel to each other such that a linedrawn perpendicular to side 98 a intersects side 98 c at a right angleG. FIG. 9E depicts kite 99. Kite 99 includes two sides 100 and two sides102, where sides 100 are of equal length, and sides 102 are of an equallength that is different than the length of sides 100. Sides 100 mayintersect with sides 102 to form angles H. Sides 100 may intersect witheach other to form angle I, and sides 102 may intersect with each otherto form angle J. Additionally, lines drawn between the corners of theintersection of sides 100, sides 102, and both intersections of sides100 and 102 may cross each other at a right angle, as indicated in FIG.9E.

In some embodiments, endoprosthesis 20 may further include a coveringlayer, such as a polymeric layer, covering the wires 21 of theendoprosthesis 20, such as a portion of the wires 21 or the entireendoprosthesis 20. In some embodiments, the covering layer, e.g.,polymeric layer, may be disposed at least partially around the one ormore wires 21. However, in other embodiments, the one or more wires 21may be disposed at least partially around the covering layer, e.g.,polymeric layer. In general, the covering layer may be formed of anydesired material, such as a textile material, a polymeric material, orother material. For example, the covering layer, in the form of apolymeric layer, may be formed of any desired polymeric material inorder to give endoprosthesis 20 any desired properties. In someembodiments, the polymeric layer may be formed of a biocompatiblematerial such as polyurethane or silicone. In some examples, thepolymeric layer may have a thickness between 0.1 mm and 1.5 mm, orbetween 0.3 mm and 1.3 mm, and in some instances may be 0.5 mm, 1.0 mm,or 1.25 mm thick.

FIGS. 10-14 depict example cross-sectional views of endoprosthesis 20including both one or more wires 21 forming a framework and coveringlayer 200 covering the framework. As depicted in FIGS. 10-14, coveringlayer 200 may have both an outer wall surface 202 and an inner wallsurface 204. In the embodiment of FIG. 10, endoprosthesis 20 may haveone or more wires 21 with a cross-section similar to that described withrespect to FIGS. 3 and 4, including at least a first tapered point 43.Additionally, in the embodiment of FIG. 10, the covering layer 200 maycover the framework such that the one or more wires 21 may be disposedcompletely around covering layer 200. For example, the entirety of theone or more wires 21 may be disposed radially further away from centrallongitudinal axis 47 than outer wall surface 202 of covering layer 200.Accordingly, faces 45 may be disposed in contact with outer wall surface202 of covering layer 200. In some embodiments, the one or more wires 21may be glued or otherwise secured to outer wall surface 202 of coveringlayer 200, but this is not required. As described with respect toprevious FIGS., although FIG. 10 depicts faces 45 as generally parallelto central longitudinal axis 47, in other embodiments, the one or morewires 21 may be disposed rotated with respect to central longitudinalaxis 47 such that faces 45 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 11, the covering layer 200 may cover theframework such that the one or more wires 21 may only be partiallydisposed around covering layer 200. For instance, first tapered points43 may be disposed radially further away from central longitudinal axis47 than outer wall surface 202 of covering layer 200. However, outerwall surface 202 of covering layer 200 may be disposed radially furtheraway from central longitudinal axis 47 than second and third taperedpoints 49, 51. However, second and third tapered points 49, 51 may stillbe disposed radially further away from central longitudinal axis 47 thaninner wall surface 204 of covering layer 200. In such embodiments,second and third tapered points 49, 51 may be embedded within coveringlayer 200. Although FIG. 11 depicts both second and third tapered points49, 51 embedded within covering layer 200, in other embodiments only oneof second and third tapered points 49, 51 may be embedded withincovering layer 200. In such embodiments, the other of second and thirdtapered points 49, 51 may be disposed radially further away from centrallongitudinal axis 47 than outer wall surface 202 of covering layer 200.Additionally, although FIG. 11 depicts faces 45 as generally parallel tocentral longitudinal axis 47, in other embodiments, the one or morewires 21 may be disposed rotated with respect to central longitudinalaxis 47 such that faces 45 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 12, the covering layer 200 may cover theframework such that at least a portion of the one or more wires 21 maybe disposed radially closer to central longitudinal axis 47 than innerwall surface 204 of covering layer 200 while at least a portion of theone or more wires 21 may be disposed radially further away from centrallongitudinal axis 47 than outer wall surface 202 of covering layer 200.For instance, first tapered points 43 may be disposed radially furtheraway from central longitudinal axis 47 than outer wall surface 202 ofcovering layer 200, while second and third tapered points 49, 51 may bedisposed radially closer to central longitudinal axis 47 than inner wallsurface 204 of covering layer 200. In these embodiments, covering layer200 may be disposed in open cells 30 between the one or more wires 21.Further, although depicted in FIG. 12 with both second and third taperedpoints 49, 51 disposed radially closer to central longitudinal axis 47than inner wall surface 204 of covering layer 200, in other embodiments,only one of second and third tapered points 49, 51 may be disposedradially closer to central longitudinal axis 47 than inner wall surface204 of covering layer 200. In these examples, the other of second andthird tapered points 49, 51 may be embedded within covering layer 200 ordisposed radially further away from central longitudinal axis 47 thanouter wall surface 202 of covering layer 200. Additionally, althoughFIG. 12 depicts faces 45 as generally parallel to central longitudinalaxis 47, in other embodiments, the one or more wires 21 may be disposedrotated with respect to central longitudinal axis 47 such that faces 45extend at any angle with respect to central longitudinal axis 47.

In the embodiment of FIG. 13, the covering layer 200 may cover theframework such that covering layer 200 may disposed at least partiallyaround the one or more wires 21. For instance, outer wall surface 202 ofcovering layer 200 may be disposed radially further away from centrallongitudinal axis 47 than first tapered points 43 where first taperedpoints 43 contact covering layer 200. However, in at least some of theseembodiments, first tapered points 43 may be disposed radially furtheraway from central longitudinal axis 47 than inner wall surface 204 ofcovering layer 200. In these embodiments, first tapered points 43 may beembedded within covering layer 200. Additionally in these embodiments,second and third tapered points 49, 51 may be disposed radially closerto central longitudinal axis 47 than inner wall surface 204 of coveringlayer 200. Although, in some embodiments, only one of second and thirdtapered points 49, 51 may be disposed radially closer to centrallongitudinal axis 47 than inner wall surface 204 of covering layer 200.The other of second and third tapered points 49, 51 may be disposedradially further away from central longitudinal axis 47 than inner wallsurface 204 of covering layer 200 and embedded within covering layer200. In these embodiments, covering layer 200 may be disposed at leastpartially in open cells 30 between the one or more wires 21. In some ofthese embodiments, outer wall surface 202 of covering layer 200 mayinclude bumps 206 where first tapered points 43 are embedded withincovering layer 200 (and may include additional bumps 206 in embodimentswhere other tapered points are embedded within covering layer 200).Additionally, although FIG. 13 depicts faces 45 as generally parallel tocentral longitudinal axis 47, in other embodiments, the one or morewires 21 may be disposed rotated with respect to central longitudinalaxis 47 such that faces 45 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 14, the covering layer 200 may cover theframework such that the entirety of covering layer 200 may be disposedcompletely over the one or more wires 21. For instance, both outer wallsurface 202 and inner wall surface 204 of covering layer 200 may bedisposed radially further away from central longitudinal axis 47 thanall of the one or more wires 21, including first tapered points 43,where the one or more wires 21 contact covering layer 200 at anycross-section perpendicular to the longitudinal axis 47. In theseembodiments, covering layer 200 may be disposed at least partially inopen cells 30 between the one or more wires 21. In some of theseembodiments, outer wall surface 202 of covering layer 200 may includebumps 206 proximate first tapered points 43. Additionally, although FIG.14 depicts faces 45 as generally parallel to central longitudinal axis47, in other embodiments, the one or more wires 21 may be disposedrotated with respect to central longitudinal axis 47 such that faces 45extend at any angle with respect to central longitudinal axis 47.

FIGS. 15-19 depict additional alternative cross-sectional views ofendoprosthesis 20 including both one or more wires 21 forming aframework and covering layer 200 covering the framework. As depicted inFIGS. 15-19, covering layer 200 may have both an outer wall surface 202and an inner wall surface 204. In the embodiment of FIG. 15,endoprosthesis 20 may have one or more wires 21 with a cross-sectionsimilar to that described with respect to FIGS. 5 and 6, including atleast a first tapered point 61 and a second tapered point 65.Additionally, in the embodiment of FIG. 15, the covering layer 200 maycover the framework such that the one or more wires 21 may be disposedcompletely around covering layer 200. For example, the entirety of theone or more wires 21 may be disposed radially further away from centrallongitudinal axis 47 than outer wall surface 202 of covering layer 200.However, the one or more wires 21 may be disposed in contact with outerwall surface 202 of covering layer 200. In some embodiments, the one ormore wires 21 may be glued or otherwise secured to outer wall surface202 of covering layer 200, but this is not required. As described withrespect to previous FIGS., although FIG. 15 depicts first and secondtapered points 61, 65 as extending generally perpendicular to centrallongitudinal axis 47, in other embodiments, the one or more wires 21 maybe disposed rotated with respect to central longitudinal axis 47 suchthat first and second tapered points 61, 65 extend at any angle withrespect to central longitudinal axis 47.

In the embodiment of FIG. 16, the covering layer 200 may cover theframework such that the one or more wires 21 may only be partiallydisposed around covering layer 200. For instance, first tapered points61 may be disposed radially further away from central longitudinal axis47 than outer wall surface 202 of covering layer 200. However, outerwall surface 202 of covering layer 200 may be disposed radially furtheraway from central longitudinal axis 47 than second tapered points 65. Insome embodiments, second tapered points 65 may still be disposedradially further away from central longitudinal axis 47 than inner wallsurface 204 of covering layer 200. In such embodiments, second taperedpoints 65 may be embedded within covering layer 200. Although FIG. 16depicts both third and fourth tapered points 63, 67 disposed radiallyfurther away from central longitudinal axis 47 than outer wall surface202 of covering layer 200, in other embodiments one or more of third andfourth tapered points 63, 67 may be embedded within covering layer 200.In these embodiments, covering layer 200 may be disposed at leastpartially in open cells 30 between the one or more wires 21.Additionally, although FIG. 16 depicts first and second tapered points61, 65 as extending generally perpendicular to central longitudinal axis47, in other embodiments, the one or more wires 21 may be disposedrotated with respect to central longitudinal axis 47 such that first andsecond tapered points 61, 65 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 17, the covering layer 200 may cover theframework such that at least a portion of the one or more wires 21 maybe disposed radially closer to central longitudinal axis 47 than innerwall surface 204 of covering layer 200 while at least a portion of theone or more wires 21 may be disposed radially further away from centrallongitudinal axis 47 than outer wall surface 202 of covering layer 200.For instance, first tapered points 61 may be disposed radially furtheraway from central longitudinal axis 47 than outer wall surface 202 ofcovering layer 200, while second tapered points 65 may be disposedradially closer to central longitudinal axis 47 than inner wall surface204 of covering layer 200. In these embodiments, covering layer 200 maybe disposed in open cells 30 between the one or more wires 21. Further,although depicted in FIG. 17 with both third and fourth tapered points63, 67 embedded within covering layer 200, in other embodiments only oneof third and fourth tapered points 63, 67 may be embedded with the otherof third and fourth tapered points 63, 67 disposed either radiallycloser to central longitudinal axis 47 than inner wall surface 204 ofcovering layer 200 or radially further away from central longitudinalaxis 47 than outer wall surface 202 of covering layer 200. Additionally,although FIG. 17 depicts first and second tapered points 61, 65 asextending generally perpendicular to central longitudinal axis 47, inother embodiments, the one or more wires 21 may be disposed rotated withrespect to central longitudinal axis 47 such that first and secondtapered points 61, 65 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 18, the covering layer 200 may cover theframework such that covering layer 200 may disposed at least partiallyaround the one or more wires 21. For instance, outer wall surface 202 ofcovering layer 200 may be disposed radially further away from centrallongitudinal axis 47 than first tapered points 61 where first taperedpoints 61 contact covering layer 200. However, in at least some of theseembodiments, first tapered points 61 may be disposed radially furtheraway from central longitudinal axis 47 than inner wall surface 204 ofcovering layer 200. In these embodiments, first tapered points 61 may beembedded within covering layer 200. Further, although depicted in FIG.18 with both third and fourth tapered points 63, 67 embedded withincovering layer 200, in other embodiments only one of third and fourthtapered points 63, 67 may be embedded with the other of third and fourthtapered points 63, 67 disposed either radially closer to centrallongitudinal axis 47 than inner wall surface 204 of covering layer 200or radially further away from central longitudinal axis 47 than outerwall surface 202 of covering layer 200. In these embodiments, coveringlayer 200 may be disposed at least partially in open cells 30 betweenthe one or more wires 21. In some of these embodiments, outer wallsurface 202 of covering layer 200 may include bumps 206 where firsttapered points 61 are embedded within covering layer 200 (and mayinclude additional bumps 206 in embodiments where other tapered pointsare embedded within covering layer 200). Additionally, although FIG. 18depicts first and second tapered points 61, 65 as extending generallyperpendicular to central longitudinal axis 47, in other embodiments, theone or more wires 21 may be disposed rotated with respect to centrallongitudinal axis 47 such that first and second tapered points 61, 65extend at any angle with respect to central longitudinal axis 47.

In the embodiment of FIG. 19, the covering layer 200 may cover theframework such that the entirety of covering layer 200 may disposedcompletely over the one or more wires 21. For instance, both outer wallsurface 202 and inner wall surface 204 of covering layer 200 may bedisposed radially further away from central longitudinal axis 47 thanall of the one or more wires 21, including first tapered points 61,where the one or more wires 21 contact covering layer 200 at anycross-section perpendicular to the longitudinal axis 47. In theseembodiments, covering layer 200 may be disposed at least partially inopen cells 30 between the one or more wires 21. In some of theseembodiments, outer wall surface 202 of covering layer 200 may includebumps 206 proximate first tapered points 61. Additionally, although FIG.19 depicts first and second tapered points 61, 65 as extending generallyperpendicular to central longitudinal axis 47, in other embodiments, theone or more wires 21 may be disposed rotated with respect to centrallongitudinal axis 47 such that first and second tapered points 61, 65extend at any angle with respect to central longitudinal axis 47.

FIGS. 20-24 depict additional alternative cross-sectional views ofendoprosthesis 20 including both one or more wires 21 forming aframework and covering layer 200 covering the framework. As depicted inFIGS. 20-24, covering layer 200 may have both an outer wall surface 202and an inner wall surface 204. In the embodiment of FIG. 20,endoprosthesis 20 may have one or more wires 21 with a cross-sectionsimilar to that described with respect to FIGS. 7 and 8, including atleast a first tapered point 71, a second tapered point 75, and a firstprojection 73. Additionally, in the embodiment of FIG. 20, the coveringlayer 200 may cover the framework such that the one or more wires 21 maybe disposed completely around covering layer 200. For example, theentirety of the one or more wires 21 may be disposed radially furtheraway from central longitudinal axis 47 than outer wall surface 202 ofcovering layer 200. However, the one or more wires 21 may be disposed incontact with outer wall surface 202 of covering layer 200. In someembodiments, the one or more wires 21 may be glued or otherwise securedto outer wall surface 202 of covering layer 200, but this is notrequired. As described with respect to previous FIGS., although FIG. 20depicts first and second tapered points 71, 75 as extending generallyperpendicular to central longitudinal axis 47, in other embodiments, theone or more wires 21 may be disposed rotated with respect to centrallongitudinal axis 47 such that first and second tapered points 71, 75extend at any angle with respect to central longitudinal axis 47.

In the embodiment of FIG. 21, the covering layer 200 may cover theframework such that the one or more wires 21 may only be partiallydisposed around covering layer 200. For instance, first tapered points71 may be disposed radially further away from central longitudinal axis47 than outer wall surface 202 of covering layer 200. However, outerwall surface 202 of covering layer 200 may be disposed radially furtheraway from central longitudinal axis 47 than second tapered points 75. Insome embodiments, second tapered points 75 may still be disposedradially further away from central longitudinal axis 47 than inner wallsurface 204 of covering layer 200. In such embodiments, second taperedpoints 75 may be embedded within covering layer 200. Although FIG. 21depicts both first and second projections 73, 77 disposed radiallyfurther away from central longitudinal axis 47 than outer wall surface202 of covering layer 200, in other embodiments one or more of first andsecond projections 73, 77 may be embedded within covering layer 200. Inthese embodiments, covering layer 200 may be disposed at least partiallyin open cells 30 between the one or more wires 21. Additionally,although FIG. 21 depicts first and second tapered points 71, 75 asextending generally perpendicular to central longitudinal axis 47, inother embodiments, the one or more wires 21 may be disposed rotated withrespect to central longitudinal axis 47 such that first and secondtapered points 71, 75 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 22, the covering layer 200 may cover theframework such that at least a portion of the one or more wires 21 maybe disposed radially closer to central longitudinal axis 47 than innerwall surface 204 of covering layer 200 while at least a portion of theone or more wires 21 may be disposed radially further away from centrallongitudinal axis 47 than outer wall surface 202 of covering layer 200.For instance, first tapered points 71 may be disposed radially furtheraway from central longitudinal axis 47 than outer wall surface 202 ofcovering layer 200, while second tapered points 75 may be disposedradially closer to central longitudinal axis 47 than inner wall surface204 of covering layer 200. In these embodiments, covering layer 200 maybe disposed in open cells 30 between the one or more wires 21. Further,although depicted in FIG. 22 with both first and second projections 73,77 embedded within covering layer 200, in other embodiments only one offirst and second projections 73, 77 may be embedded with the other offirst and second projections 73, 77 disposed either radially closer tocentral longitudinal axis 47 than inner wall surface 204 of coveringlayer 200 or radially further away from central longitudinal axis 47than outer wall surface 202 of covering layer 200. Additionally,although FIG. 22 depicts first and second tapered points 71, 75 asextending generally perpendicular to central longitudinal axis 47, inother embodiments, the one or more wires 21 may be disposed rotated withrespect to central longitudinal axis 47 such that first and secondtapered points 71, 75 extend at any angle with respect to centrallongitudinal axis 47.

In the embodiment of FIG. 23, the covering layer 200 may cover theframework such that covering layer 200 may disposed at least partiallyaround the one or more wires 21. For instance, outer wall surface 202 ofcovering layer 200 may be disposed radially further away from centrallongitudinal axis 47 than first tapered points 71 where first taperedpoints 71 contact covering layer 200. However, in at least some of theseembodiments, first tapered points 71 may be disposed radially furtheraway from central longitudinal axis 47 than inner wall surface 204 ofcovering layer 200. In these embodiments, first tapered points 71 may beembedded within covering layer 200. Further, in various differentembodiments, first and second projections 73, 77 may be embedded withincovering layer 200, may be disposed radially closer to centrallongitudinal axis 47 than inner wall surface 204 of covering layer 200,or may be disposed radially further away from central longitudinal axis47 than outer wall surface 202 of covering layer 200. In at least someembodiments, first and second projections 73, 77 may disposed indifferent locations with respect to each other. In these embodiments,covering layer 200 may be disposed at least partially in open cells 30between the one or more wires 21. In some of these embodiments, outerwall surface 202 of covering layer 200 may include bumps 206 where firsttapered points 71 is embedded within covering layer 200 (and may includeadditional bumps 206 in embodiments where other tapered points areembedded within covering layer 200). Additionally, although FIG. 23depicts first and second tapered points 71, 75 as extending generallyperpendicular to central longitudinal axis 47, in other embodiments, theone or more wires 21 may be disposed rotated with respect to centrallongitudinal axis 47 such that first and second tapered points 71, 75extend at any angle with respect to central longitudinal axis 47.

In the embodiment of FIG. 24, the covering layer 200 may cover theframework such that the entirety of covering layer 200 may disposedcompletely over the one or more wires 21. For instance, both outer wallsurface 202 and inner wall surface 204 of covering layer 200 may bedisposed radially further away from central longitudinal axis 47 thanall of the one or more wires 21, including first tapered points 71,where the one or more wires contacts covering layer 200 at anycross-section perpendicular to the longitudinal axis 47. In theseembodiments, covering layer 200 may be disposed at least partially inopen cells 30 between the one or more wires 21. In some of theseembodiments, outer wall surface 202 of covering layer 200 may includebumps 206 proximate first tapered points 71. Additionally, although FIG.24 depicts first and second tapered points 71, 75 as extending generallyperpendicular to central longitudinal axis 47, in other embodiments, theone or more wires 21 may be disposed rotated with respect to centrallongitudinal axis 47 such that first and second tapered points 71, 75extend at any angle with respect to central longitudinal axis 47.

FIGS. 25-27 depict example cross-sections of endoprosthesis 20 inaccordance with the present disclosure at various stages of manufacture.In one example method, the one or more wires 21 are woven to createwoven wire framework 22, including open cells 30. Next, a compliantfiller 101 is inserted into lumen 28 of woven wire framework 22. FIG. 25depicts a cross-section of endoprosthesis 20 at this stage. Compliantfiller 101 may be a compliant solid rod or a compliant hollow tube, acompressible foam, or a curable material, for example. In someinstances, the compliant filler 101 may be made out of a polymermaterial. In some embodiments, compliant filler 101 may have an outerdiameter that is greater than the inner diameter of woven wire framework22 as measured from one wire 21 to another wire 21 across lumen 28. Insuch embodiments, due to the compliant nature of compliant filler 101,portions 103 of compliant filler 101 may extend radially out into opencells 30 between the one or more wires 21. In some embodiments, aportion of wires 21, such as tapered points, may extend radially outwardbeyond the outer extent of the compliant filler 101.

Once compliant filler 101 is in place, a liquid material, such as apolymeric material, may be applied to the wire framework 22, such asduring a spray coating or dip coating process, resulting in liquidmaterial flowing into open cells 30. Once the liquid material is inplace, the liquid material may be cured or hardened into a solidmaterial, such as by application of heat, electricity, ultravioletlight, or a cross-linking agent, for example. After curing or hardening,the liquid material may form covering layer 200. FIG. 26 depicts across-section of endoprosthesis 20 at this stage.

Thereafter, compliant filler 101 may be removed from endoprosthesis 20.FIG. 27 depicts an example cross-section of endoprosthesis 20 withcompliant filler 101 removed, leaving covering material spanning cells30 between adjacent wires 22. In this way, an endoprosthesis 20 similarto those described with respect to FIGS. 12, 17, and 22 may be formed.

In additional or alternative embodiments, a liquid material, such as apolymeric material, may be applied to the wire framework 22, such asduring a spray coating or dip coating process. In these embodiments,after hardening of the liquid material, endoprosthesis 20 may have astructure similar to that described with respect to FIGS. 13, 14, 18,19, and/or 23, 24.

In still additional or alternative embodiments, instead of using aliquid material, a solid cover material in the shape of a hollow tube orsheath may be positioned over the one or more wires 21 and may bedisposed at least partially in open cells 30. Once the cover material isin place in open cells 30, the cover material forms covering layer 200having an outer wall surface 202 and an inner wall surface 204. Someexample cover materials include various polymers. In some embodiments,the cover material may be heat-shrunk or otherwise made to closelyconform to the one or more wires 21.

FIGS. 28 and 29 depict example cross-sections of endoprosthesis 20during another method of making an endoprosthesis 20 in accordance withthe present disclosure. FIG. 28 depicts a cross-section of mandrel 111covered by covering layer 200, such as a polymeric tubular member,having an outer wall surface 202 and an inner wall surface 204. Next,one or more wires 21 may be woven over mandrel 111 and covering layer200 to form endoprosthesis 20, as depicted in FIGS. 29A and 29B incross-section. FIG. 29A depicts the one or more wires 21 as triangleswoven with faces 45 generally flat against to outer surface 202 ofcovering layer 200 with the one or more wires 21 disposed completelyfurther away from the center of mandrel 111 than outer wall surface 202of covering layer 200. FIG. 29B, in contrast, depicts an embodimentwhere wires 21 are generally diamond shaped and where at least a portionof the one or more wires 21 are be embedded within covering layer 200.That is, at least a portion of the one or more wires 21 are disposedcloser to the center of mandrel 111 than outer wall surface 202 ofcovering layer 200. It should be understood that the specific shapes ofwires 21 of FIGS. 29A and 29B are only exemplary, and in otherembodiments, wires 21 having other shapes may be used. Additionally, inother embodiments, the one or more wires 21 may be rotated with respectto mandrel 111 and covering layer 200 such that one or more of taperedpoints 43, 49, and 51 may be pointed inward toward mandrel 111 andcovering layer 200. In this way, an endoprosthesis 20 similar to thosedescribed with respect to FIGS. 10, 11, 15, 16, and/or 20, 21 may beformed.

FIG. 30 is a flow diagram illustrating a method that may be used to forman endoprosthesis 20 in accordance with the present disclosure, forexample those described with respect to FIGS. 10-24. The method maybegin by weaving, such as braiding, a plurality of wires to form a stentcomprising a plurality of open cells, the stent having a central hollowregion, at least one of the plurality of wires having a cross-sectionincluding a first tapered point, as at 3001. The method may furtherinclude inserting a compliant filler into the central hollow region ofthe stent, as at 3003. The method may then include covering, e.g.,coating, the stent and the compliant filler with a cover material, as at3005. Finally, the method may include removing the compliant fillerdevice, as at 3007.

Those skilled in the art will recognize that aspects of the presentdisclosure may be manifested in a variety of forms other than thespecific embodiments described and contemplated herein. Accordingly,departure in form and detail may be made without departing from thescope and spirit of the present disclosure as described in the appendedclaims.

What is claimed is:
 1. An implantable medical device for implantationwithin a passageway of a patient, the device comprising: a tubularframework including a plurality of interwoven wires, at least one of theplurality of interwoven wires comprising a cross-section having a firsttapered point and a second tapered point opposite the first taperedpoint, the cross-section of the at least one wire taken transverse to alongitudinal length of the wire such that the first and second taperedpoints extend along the longitudinal length of the wire; a coveringlayer having a central longitudinal axis and an inner diameter and anouter diameter; wherein the covering layer covers at least a portion ofthe framework and extends between adjacent wires of the plurality ofinterwoven wires included in the portion of the framework.
 2. Theimplantable medical device of claim 1, wherein the first and secondtapered points extend perpendicular to the central longitudinal axis. 3.The implantable medical device of claim 1, wherein the first and secondtapered points extend at an angle to the central longitudinal axis. 4.The implantable medical device of claim 1, wherein an entirety of thecovering layer is disposed completely over the plurality of interwovenwires such that an inner surface of the covering layer contacts thefirst tapered point and an outer surface of the covering layer defines abump over the first tapered point.
 5. The implantable medical device ofclaim 1, wherein the first tapered point extends outward further thanthe outer diameter of portions of the covering layer that extend betweenthe adjacent wires.
 6. The implantable medical device of claim 5,wherein the second tapered point is embedded within the covering layer.7. The implantable medical device of claim 5, wherein the second taperedpoint extends inward further than the inner diameter of the portions ofthe covering layer that extend between the adjacent wires.
 8. Theimplantable medical device of claim 1, wherein the cross-section of theat least one of the plurality of interwoven wires further comprisesthird and fourth tapered points.
 9. The implantable medical device ofclaim 8, wherein the cross-section of the at least one of the pluralityof interwoven wires is a diamond.
 10. The implantable medical device ofclaim 8, wherein the cross-section of the at least one of the pluralityof interwoven wires is a square.
 11. The implantable medical device ofclaim 8, wherein the cross-section of the at least one of the pluralityof interwoven wires is a trapezoid.
 12. The implantable medical deviceof claim 8, wherein the third and fourth tapered points are embeddedwithin the covering layer.
 13. The implantable medical device of claim1, wherein the cross-section of the at least one of the plurality ofinterwoven wires further comprises at least one rectangular projectiondisposed between the first and second tapered points.
 14. Theimplantable medical device of claim 13, wherein the at least onerectangular projection includes first and second opposing rectangularprojections.
 15. The implantable medical device of claim 14, wherein thefirst and second opposing rectangular projections are embedded withinthe covering layer.
 16. An implantable medical device for implantationwithin a passageway of a patient, the device comprising: a tubularframework including a plurality of interwoven wires, at least one of theplurality of interwoven wires comprising a cross-section having a firsttapered point oriented radially outward from a central longitudinal axisof the framework and a second tapered point oriented radially inwardtoward the central longitudinal axis of the framework, the cross-sectionof the at least one wire taken transverse to a longitudinal length ofthe wire such that the first and second tapered points extend along thelongitudinal length of the wire; and a covering layer disposed over aportion of the framework and extending between adjacent wires of theplurality of interwoven wires included in the portion of the framework;wherein the first tapered point extends radially outward further than anouter diameter of the covering layer; and wherein the second taperedpoint extends radially inward further than an inner diameter of thecovering layer.
 17. The implantable medical device of claim 16, whereinthe cross-section of the at least one of the plurality of interwovenwires further comprises third and fourth tapered points.
 18. Theimplantable medical device of claim 17, wherein the third and fourthtapered points are embedded within the covering layer.
 19. Animplantable medical device for implantation within a passageway of apatient, the device comprising: a tubular framework including aplurality of interwoven wires, at least one of the plurality ofinterwoven wires comprising a cross-section having a first tapered pointoriented radially outward from a central longitudinal axis of theframework and a second tapered point oriented radially inward toward thecentral longitudinal axis of the framework, the cross-section of the atleast one wire taken transverse to a longitudinal length of the wiresuch that the first and second tapered points extend along thelongitudinal length of the wire; and a covering layer disposed over theframework and extending between adjacent wires of the plurality ofinterwoven wires, the covering layer having an inner diameter and anouter diameter; wherein the first tapered point is embedded in thecovering layer and the second tapered point extends radially inwardfurther than the inner diameter of the covering layer.
 20. Theimplantable medical device of claim 19, wherein the cross-section of theat least one of the plurality of interwoven wires further comprisesfirst and second opposing rectangular projections disposed between thefirst and second tapered points.